QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4md

Earthquake near Brenas, PR

No earthquake was likely felt in Brenas in the 24 hours to 10:40 am AST (14:40 UTC). The last one was M 4.8, 87 km (54 mi) SW, at 9:19 am AST on 18 September 2026, estimated intensity III (weak) in town; 86 felt reports to USGS. Every earthquake near Brenas

This page: a magnitude 3.4 earthquake was recorded 9 km (5 mi) north-northeast of Brenas, PR, at 3:40 am AST on 29 April 2026 (07:40 UTC), 101 km deep.

USGS: 8 km NNE of Brenas, Puerto Rico

29 km (18 mi) WNW of San Juan, PR · 22 km (14 mi) NW of Bayamón, PR

3:40 am AST, Apr 29, 2026 · · 101 km deep · released about 1.8 tons of TNT

Every earthquake near Brenas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Dorado Municipio 8 kmVega Alta Municipio 12 kmVega Baja Municipio 14 kmToa Baja Municipio 14 kmCataño Municipio 19 kmToa Alta Municipio 20 kmManatí Municipio 23 kmBayamón Municipio 25 kmCorozal Municipio 26 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
3:40 am AST on 29 April 2026 ()
Where
9 km (5 mi) north-northeast of Brenas, PR · earthquakes near Brenas
Magnitude
M 3.4 (md)
Depth
101 km below the surface
Felt
no reports yet
Measured shaking
intensity II (ShakeMap)
Nearest
Dorado Municipio, 8 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 123 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Brenas, 9 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Dorado, San Antonio, Sabana, Toa Baja, Ceiba, Monserrate.

How big was it?

This earthquake released about 1.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 92,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,100× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,900× the energy of this one
  4. This earthquake M 3.4 about 1.8 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.8× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.8 on 2017-08-18 — about 130 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.8 12 km N of Garrochales, Puerto Rico · 28 km W of this epicentre
  2. 5.1 3 km W of Aguas Buenas, Puerto Rico · 35 km SSE of this epicentre
  3. 5.0 3 km N of Brenas, Puerto Rico · 6 km SW of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 18.5353, -66.2988. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Dorado Municipio, PR 8 km (5 mi) SSE earthquakes near Dorado Municipio
Vega Alta Municipio, PR 12 km (7 mi) SSW earthquakes near Vega Alta Municipio
Vega Baja Municipio, PR 14 km (9 mi) SW earthquakes near Vega Baja Municipio
Toa Baja Municipio, PR 14 km (9 mi) SE earthquakes near Toa Baja Municipio
Cataño Municipio, PR 19 km (12 mi) ESE earthquakes near Cataño Municipio
Toa Alta Municipio, PR 20 km (12 mi) SSE earthquakes near Toa Alta Municipio

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

30 earthquakes have been recorded within 50 km since this one.

  1. 3.0 15 km N of Arecibo, Puerto Rico
  2. 2.8 43 km NNE of Arecibo, Puerto Rico
  3. 2.2 5 km WSW of Naranjito, Puerto Rico
  4. 2.8 10 km NNE of Tierras Nuevas Poniente, Puerto Rico
  5. 2.6 5 km N of Animas, Puerto Rico
  6. 3.1 36 km NNE of Arecibo, Puerto Rico
  7. 2.4 19 km NNE of Arecibo, Puerto Rico
  8. 2.3 4 km N of Brenas, Puerto Rico
  9. 2.9 7 km NNE of Brenas, Puerto Rico
  10. 2.7 5 km SW of Guaynabo, Puerto Rico
  11. 2.9 29 km N of San Juan, Puerto Rico
  12. 2.1 2 km W of Garrochales, Puerto Rico
  13. 2.8 15 km NNE of Dorado, Puerto Rico
  14. 3.1 0 km WNW of Monserrate, Puerto Rico
  15. 2.7 41 km N of Brenas, Puerto Rico

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.